Acknowledgements

I am indebted to the researchers and construction professionals who readily gave permission for the inclusion of their work in the text. These include Dr Koen Steemers of Cambridge Architectural Research, Arup Associates for BedZED diagrams, Christopher John Hancock for the images of Malmo, Jeremy Stacy Architects for the Council Offices, King's Lynn, Fielden Clegg Bradley for the National Trust Offices, Swindon, XCO2 for the triple helix wind generator image and Pilkington plc for the image of Herne Sodingen government training centre. I also owe my thanks to Dr Randall Thomas of Max Fordham and Partners and Robin Saunders of the Department of Mechanical Engineering, Sheffield University for reviewing the manuscript and giving me the benefit of their expertise in the sphere of renewable energy. I must also record my thanks to my wife Jeannette for her sterling work in making up for my deficiencies in proofreading. Finally, my special thanks are due to Sir John Houghton for allowing me to begin the book with his Prince Philip Lecture at the Royal Society of Arts in 2005 and to Lord Rogers of Riverside for his continued support.

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1 Climate change and sustainable energy: The 2005 Prince Philip Lecture at the Royal Society of Arts by Sir John Houghton CBE FRS

Your Royal Highness, it is a pleasure and privilege to be presenting your lecture this evening. You have been a great supporter of sustainability. In particular, you are pursuing some highly innovative sustainable energy projects at Windsor Castle that provide marvellous examples of the variety of ways forward for us in the energy field.

There is a fine exhibition in the Tate Gallery at the moment of works by Turner, Whistler and Monet. A hundred years ago, Monet spent time in London and painted wonderful pictures of the light coming through the smog. London was blighted by local pollution from domestic and industrial chimneys around the city itself. Thanks to the Clean Air Acts beginning in the 1950s, those awful smogs belong to the past, although London's atmosphere could be still cleaner.

But what I am talking about today is global pollution - emissions of gases such as carbon dioxide to which we are all contributing, that spread around the whole atmosphere and affect everybody. Global pollution requires global solutions.

Let me start with a quick summary of some of the science of global warming. By absorbing infrared or 'heat' radiation from the Earth's surface, 'greenhouse gases' present in the atmosphere - such as water vapour and carbon dioxide - act as blankets over the Earth, keeping it warmer than it would otherwise be. The existence of this natural 'greenhouse effect' has been known for nearly two hundred years; it is essential to the provision of our current climate, to which ecosystems and we humans have adapted.

Since the beginning of the Industrial Revolution around 1750, one of these greenhouse gases - carbon dioxide - has increased by more than 30% and is now at a higher concentration in the atmosphere than it has been for many thousands of years (Fig. 1.1). Chemical analysis demonstrates that this increase is largely due to the burning of the fossil fuels coal, oil and gas. If no action is taken to curb these emissions, the carbon dioxide concentration will rise during the twenty-first century to two or three times its preindustrial level.

The climate record over the last 1,000 years (Fig. 1.2) shows a lot of natural variability, including, for instance, the 'medieval warm period' and the 'little ice age'. The rise in global

Direct measurements ppm

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Ice core data

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1600 Year

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900 800 700 600 500 400 300 200 100 0

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Figure 1.1 Concentration of carbon dioxide in the atmosphere from 1000 AD and projected to 2100 under typical IPCC scenarios average temperature (and its rate of rise) during the twentieth century is well outside the range of known natural variability. The year 1998 is the warmest in the instrumental record. A more striking statistic is that each of the first 8 months of 1998 was the warmest on record for that month. There is strong evidence that most of the warming over the last 50 years is due to the increase of greenhouse gases, especially carbon dioxide. Confirmation of this is also provided by observations of the warming of the oceans. The period of 'global dimming' from about 1950 to 1970 is most likely due to the increase in atmospheric particles (especially sulphates) from industrial sources. These particles reflect sunlight, hence tending to cool the surface and mask some of the warming effect of greenhouse gases.

Over the twenty-first century the global average temperature is projected to rise by between 2 and 6°C (3.5 to 11°F) from its preindustrial level - the range represents different assumptions about emissions of greenhouse gases and the sensitivity of the climate model used in making the estimate (Fig. 1.2). For global average temperature, a rise of this amount is large. Its difference between the middle of an ice age and the warm periods in between is only about 5 or 6°C (9 to 11°F). So, associated with likely warming in the twenty-first century will be a rate of change of climate equivalent to, say, half an ice age in less than 100 years - a larger rate of change than for at least 10,000 years. Adapting to this will be difficult for humans and many ecosystems.

Talking in terms of changes of global average temperature, however, tells us rather little about the impacts of global warming on human communities. Some of the most obvious impacts will be due to the rise in sea level that occurs because ocean water expands as it is heated. The projected rise is of the order of half a metre (20 inches) a century and will continue for many centuries - to warm the deep oceans as well as the surface waters takes a long time. This will cause large problems for human communities living in low lying regions. Many areas - for instance Bangladesh (where about 10 million live within the one metre contour -Fig. 1.3), southern China, islands in the Indian and Pacific oceans and similar places elsewhere in the world - will be impossible to protect and many millions of people will be displaced.

Variations of the Earth's surface temperature: 1000 to 2100

1000 to 1861, N. Hemisphere, proxy data; 1861 to 2000 Global, instrumental; 2000 to 2100, SRES projections

Variations of the Earth's surface temperature: 1000 to 2100

1000 to 1861, N. Hemisphere, proxy data; 1861 to 2000 Global, instrumental; 2000 to 2100, SRES projections

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Figure 1.2 Variations of the average near-surface air temperature: 1000-1861, N Hemisphere from proxy data; 1861-2000, global instrumental; 2000-2100, under a range of IPCC projections with further shading to indicate scientific uncertainty

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Figure 1.2 Variations of the average near-surface air temperature: 1000-1861, N Hemisphere from proxy data; 1861-2000, global instrumental; 2000-2100, under a range of IPCC projections with further shading to indicate scientific uncertainty

There will also be impacts from extreme events. The extremely unusual high temperatures in central Europe during the summer of 2003 led to the deaths of more than 20,000 people. Careful analysis leads to the projection that such summers are likely to be average by the middle of the twenty-first century and cool by the year 2100.

Water is becoming an increasingly important resource. A warmer world will lead to more evaporation of water from the surface, more water vapour in the atmosphere and more precipitation on average. Of greater importance is the fact that the increased condensation of water vapour in cloud formation leads to increased latent heat of condensation being released. Since this latent heat release is the largest source of energy driving the atmosphere's circulation, the hydrological cycle will become more intense. This means a tendency to more intense rainfall events and also less rainfall in some semi-arid areas. Since, on average, floods and droughts are the most damaging of the world's disasters (see Table 1.1), their greater frequency and intensity is bad news for most human communities, and especially for those regions such as south east Asia and sub-Saharan Africa where such events already occur all too frequently. It is these sorts of events that provide some credence to the comparison of climate with weapons of mass destruction.

Figure 1.3 Land affected in Bangladesh by various amounts of sea-level rise Table 1.1 Major floods in the 1990s

1991, 1994-5, 1998 - China; average disaster cost, 1989-96, 4% of GDP 1993 - Mississippi & Missouri, USA; flooded area equal to one of great lakes

1997 - Europe; 162,000 evacuated and >$5bn loss

1998 - Hurricane Mitch in central America; 9,000 deaths, economic loss in Honduras &

Nicaragua, 70% and 45% of GDP

1999 - Venezuela; flooding led to landslide, 30,000 deaths

2000-1 - Mozambique; two floods left more than half a million homeless

Sea-level rise, changes in water availability and extreme events will lead to increasing pressure from environmental refugees. A careful estimate has suggested that, due to climate change, there could be more than 150 million extra refugees by 2050.

In addition to the main impacts summarized above are changes about which there is less certainty but which, if they occurred, would be highly damaging and possibly irreversible. For instance, large changes are being observed in polar regions. If the temperature rises more than about 3°C (~5°F) in the area of Greenland, it is estimated that meltdown of the ice cap would begin. Complete meltdown is likely to take 1,000 years or more but it would add 7 metres (23 feet) to the sea level.

A further concern is regarding the thermo-haline circulation (THC) - a circulation in the deep oceans, partially sourced from water that has moved in the Gulf Stream from the tropics to the region between Greenland and Scandinavia. Because of evaporation on the way, the water is not only cold, but salty, and hence of higher density than the surrounding water. It therefore tends to sink and provides the source for a slow circulation at low levels that connects all the oceans together. This sinking assists in maintaining the Gulf Stream itself. In a globally warmed world, increased precipitation together with fresh water from melting ice will decrease the water's salinity, making it less likely to sink. The circulation will therefore weaken and possibly even cut off, leading to large regional changes of climate. Evidence from paleoclimate history shows that such cut-off has occurred at times in the past. It is such an event that is behind the highly speculative happenings in the film The Day After Tomorrow.

I have spoken so far about adverse impacts. You will ask: 'are none of the impacts positive?' There are some positive impacts. For instance, in Siberia and other areas at high northern latitudes, winters will be less cold and growing seasons will be longer. Also, increased concentrations of carbon dioxide have a fertilizing effect on some plants and crops which, providing there are adequate supplies of water and nutrients, will lead to increased crop yields in some places, probably most notably in northern mid-latitudes. However, careful studies demonstrate that adverse impacts will far outweigh positive effects; more so as temperatures rise more than 1 or 2°C (2 to 3.5°F) above preindustrial.

Many people ask how sure we are about the scientific story I have just presented. Let me explain that it is based very largely on the extremely thorough work of the Intergovernmental Panel on Climate Change (IPCC) and its last major report published in 2001. The scientific literature on climate change has increased enormously over the last decade. The basic science of anthropogenic climate change has been confirmed. The main uncertainties lie in our knowledge of feedbacks in the climate system, especially those associated with the effects of clouds. Recent research has tended to indicate increased likelihood of the more damaging impacts.

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